<p>Asphalt binder typically exhibits nonlinear rheological properties under substantial loads in actual pavement applications. However, due to insufficient research on nonlinearity, the rheological properties of asphalt binder are incorrectly evaluated, which leads to a reduction in the safety and reliability of pavements. To address the problem, this paper studies the effect of rubber powder on the linear and nonlinear rheology of neat asphalt binder. The linear rheology of rubber modified asphalt binder is characterized by modulus and phase angle master curves. The nonlinearity of rubber modified asphalt binder under large amplitude oscillatory shear loading (LAOS stress) is investigated by Fourier Transform Rheology (FT-rheology) and strain decomposition. The linearity measurements show that the elastic composition and the complexity of the rheological behavior of rubber modified asphalt binder increase with increasing dosage. The nonlinearity measurements show that the nonlinearity of rubber modified asphalt binder increases with increasing stress and decreasing mesh size. In addition, and stress level follow the same trend, indicating that the nonlinearity becomes more and more prominent with increasing stresses. The analysis of FT-rheology and strain decomposition show that the nonlinearity of rubber modified asphalt binder is better than that of neat asphalt binder, and the nonlinearity becomes more obvious with increasing dosage and decreasing mesh size. In brief, high-dosage and low-mesh rubber powder can improve the elastic proportion and nonlinearity of neat asphalt binder, leading a superior pavement performance under heavy traffic loads. Stress softening and shearing thinning are observed in all asphalt binders under the studied conditions.</p>